As we’ve been documenting in our ongoing series, political parties and other powerful players use the once-a-decade redistricting process to advance their own goals–often at the expense of voters.

A recently released trove of e-mails from Ohio offers a rare inside glimpse into how it works.

The e-mails, sent from June to September, show collaboration between the national GOP and state Republicans to re-draw Ohio’s map and thus cement control of both the statehouse and a majority of congressional districts.

In one of the emails, a Republican consultant working on redistricting for the state suggested that the new political maps could save the GOP “millions” of dollars in campaign funds by making districts safer for Republican candidates.

The maps, approved by the Republican-run state legislature in September, favor Republicans in 12 of Ohio’s 16 congressional districts. And they strengthen the majority of likely Republican supporters in at least 17 state house districts, according to the mapping consultants’ own calculations.

A spokesman for Ohio’s House of Representatives said that the e-mails and the accompanying report released by the Ohio Campaign for Accountable Redistricting were an attempt to garner “salacious” and “malicious” headlines. According to Mike Dittoe, director of communications for the Ohio House of Representatives and for Republican Speaker Bill Batchelder, Ohio’s redistricting was “a fully transparent process that yielded a fair and legal map.”

Redistricting is supposed to benefit voters by equalizing districts as the nation’s population shifts. But with few strict requirements for how to shape districts-they must have roughly equal populations and not discriminate against minority voters- political parties often can draw political lines largely to their own benefit.

Much of the time, the toughest balancing act in the map-drawing process is how to please multiple incumbents at once.

In the e-mails obtained by the Ohio Campaign for Accountable Redistricting, these kinds of partisan concerns are central. In one e-mail, the president of the state senate, Republican Thomas Niehaus, noted that “I am still committed to ending up with a map that Speaker Boehner fully supports,” even though, as a spokesman said in November, Boehnner “has no official role in the redistricting process.”

Dittoe, the House spokesman, said the state received redistricting input from many stakeholders, including all 18 of Ohio’s current congresspeople and Ray Miller, a former Democratic state politician.

The redistricting consultants also pushed through an eleventh-hour change to the maps that switched the location of the Timken Corporation back into the district of U.S. Rep. Jim Renacci. Timken is one of Renacci’s top donors. Members of the Timken family, company officials, and a company PAC have given at least $210,000 in total to Renacci in the past two years, according to the Cleveland Plain-Dealer.

“Thanks guys. Very important to someone important to us all,” Tom Whatman, the executive director of Team Boehner, wrote after the change was completed.

“In no way do campaign contributions influence how lines are drawn,” Dittoe said.

The redistricting e-mails included a consideration of partisan advantage down to the level of individual streets.

In an e-mail to Ray DiRossi, one of the two staffers responsible for drawing the state’s maps, a Republican state senator said she knew that another Republican state legislator was “looking for Republicans” in her county and suggested a list of more than 80 streets in ten neighborhoods where she had received a “good response.”

In September, as the redistricting maps were being approved, the chief of staff of the Republican state house speaker sent DiRossi a list of 43 of the state’s legislative districts, ranked according to the total amount of so-called in-kind contributions made to House races in each district.

According to the Federal Election Commission, “The donation of office machines, furniture, supplies-anything of value-is an in-kind contribution… A donation of services is also considered an in-kind contribution. ”

In nine of the districts, in-kind donations totaled more than $2 million over the past decade.

The rankings appeared to be a measure of which districts had been most competitive over the past ten years, since many of the districts that received the most in-kind contributions had alternated between Republican and Democratic control

“Ray-was running a quick analysis on inking contributions made to house races over the last decade and thought you’d find it interesting which districts were on top,” Troy Judy, House Speaker Batchelder’s chief of staff, wrote in an e-mail.

DiRossi wrote back a few minutes later, expressing surprise at the position of two of the districts on the list, and added, “But we have made significant improvements to many HDs [House districts] on this list. Hopefully saving millions over the coming years.”

DiRossi’s comment seemed to suggest that the new maps would be less competitive, and thus would require fewer campaign donations–a potential savings of millions of dollars.

“It’s 1AM–go to bed you political junkies,” Heather Mann, another of the state’s redistricting staffers, wrote back.

Dittoe said the contributions statistics were sent to several people, and that since the redistricting maps were already complete by the time the e-mail was sent, the statistics could not have prompted any changes in the maps.

DiRossi and Mann, who is currently a deputy legal counsel in Batchelder’s office, were each paid $105,000 in public money for a few months of redistricting work, according to public documents obtained by the Ohio Campaign for Accountable Redistricting.

Anything said about redistricting by politicians can be used as evidence in a legal challenge of a mapping plan-so politicians are typically warned to keep silent in public about redistricting plans. In a ProPublica interview last week, Georgia Congressman Lynn Westoreland, a point man for the Republicans’ redistricting effort, said Congressional delegations were briefed on redistricting protocol and warned that whatever they said could be used in court.

Westmoreland said he also warned congressman to work as a team and “not to get greedy.”